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This line passes the validator: <img src="http://images.paypal.com/images/x-click-but22.gif" border="0" width="87" height="23" alt="Add to Cart"></a> But this line complains there's no alt tag: <img alt="Add to Cart" src="http://images.paypal.com/images/x-click-but22.gif" border="0" width="87" height="23"></a> Note that the url above will soon change to http://cougarclub.org/Store/, in case you get a 404.
As far as I know the parser does not care about attribute order. I have taken the page you mention, shuffled the attributes around as the bug report said, and always got positive validation as a result.